"I do think it continually should be reviewed," said Hagel of the ban. "I'm open to those assessments, because, again, I go back to the bottom line, every qualified American who wants to serve our country should have an opportunity if they fit the qualifications and can do it."

Hagel said his only concern was regarding medical support for transgender troops in "austere locations." He said transgender issues in regard to military service are "an area that we’ve not defined enough," and was sure to clarify that he is not stating an opinion one way or another on keeping or repealing the ban, but simply believes it should be reviewed.

The aforementioned study released in March by a San Francisco State University think tank said there were "approximately 15,450 transgender personnel who serve currently in the active, Guard, and reserve components."

In response to the report, Navy Lt. Cmdr. Nate Christensen, a defense department spokesman, said, "At this time there are no plans to change the department's policy and regulations which do not allow transgender individuals to serve in the U.S. military."

Many countries, including Australia, Canada, the United Kingdom, and Israel, allow transgender people to serve in the military. A similar ban on gay, lesbian, and bisexual service members, commonly known as "Don't Ask, Don't Tell," was lifted in the U.S. in 2010.